To learn how both "early" and "late" functions of polyoma virus are expressed and regulated during the lytic cycle. To do this we will prepare poly(A) containing mRNAs from infected cells at different times after infection and translate these mRNAs in a variety of cell free systems. Virus specific mRNAs will be isolated by hybridization to polyoma DNA covalently bound to cellulose. Preparations of virus specific mRNAs will be fractionated according to size to determine the number of different species. Purified mRNAs will be translated to determine which species they code for. Particular attention will be paid to the in vitro products from "early" mRNAs to see whether there is more than one polypeptide chain coded for by the "early" region, which might help to explain the multi-functionality of this region. We will also investigate the hypothesis that one of the major capsid proteins regulates "late" viral transcription. BIBLIOGRAPHIC REFERENCES: Robbins, J.C., Hunter, T.R., and Nicolson, G.L. (1977). Ricinus communis toxin-mediated inhibition of protein synthesis in cell-free extracts of a toxin resistant variant mouse lymphoma line. J. Supramol. Struc. Gibson, W., Hunter, T., Cogen, B., and Eckhart, W. (1977). Altered vision proteins of a temperature sensitive mutant of polyoma virus, ts 59. Virology.